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Discussion Starter #1
Hi guys on my crown victoria with the 4.6 with the car running cold before the fan turns on the volt gauge reads between 13.3v to 13.7 volts with no noises or anything when the fan kicks on around 198 degrees the voltage slowly drops 12.3 12.1 until 11.6 sometimes.

I installed a supercharger on the car before the supercharger the car would read 14.1 on start up and 13.6 with the fan on. I still have the stock 135 amp alternator which tested good at 14.3 on the bench.

and I have an optima red top battery in the trunk could this be the problem ? I think i read somewhere that the red tops are only good for starting, do they work with supercharged engines ??

thanks:confused:
 

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hmm. The fan on my 95 bird shorted internally and would blow a fuse after it ran for about 10sec. Maybe yours is doing this as well, just not at as high of an amp draw as mine did.
-Thomas
 

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Does your car have starting issues sometimes? On my 94 cougar, it would have issues starting sometimes, and it was due to a shorted starter cable. One of the side effects would be that the voltage would really drop when the car heated up, same as what you are saying. If nothing else works, I would look into this. Also, when I did this the voltage drops I had from my turn signals went away.

Stephen
 

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Discussion Starter #4
I dont think i have a blown fuse because the fan keeps on working on and off as it should.

hm no starting issues but will sure check that cable.
 

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Discussion Starter #5
forgot to add, the vacuum sits at 20 hg as it should and I had a coil on plug engine code which I changed the cop and there was no change in the voltage.
 

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Discussion Starter #6
ok found out I had too many things hooked up to the main power stud ( alt, batt, ground, and two wires for the subs) disconnected the two wires for the subs and now it reads 13.8-14.1 , with the ac on it drops until like 13.4.

when the fan kicks on the voltage goes down to like 11.8 and slowly comes back up to 13.8.

how can the fan be using 2 volts to start ?
 

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First, are you seeing these voltages at idle or at cruise? An alternator’s output is not constant. That 130 amp stock alternator is only providing that amount of current out at full rpm.

The symptom you described is classic of an electrical system that has an alternator that is not providing enough current to handle the current demands. Or a wiring issue, so I suggest you research http://forums.tccoa.com/showthread.php?t=75792 first as that is always a good (and relatively inexpensive) starting place.

Other possible solutions are a larger alternator; larger (or second) battery (to basically provide amperage when the alternator isn’t putting out full power); or decrease the total amperage requirements.

But first I would try the “Big 3” first.

But just my .02 and good luck. :thumbsup:
 

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Discussion Starter #8
I think the " big 3 " is only for birds right? I already replaced my alt cable with a 2 or 4 gauge cable cant remember which when i did the supercharger.

I just drove it today, with the car cold at cruise it would read mid 13's and drop to 12.8 when fan kicks on but then back to mid 13's.

with the engine warm I was seeing as low as 13.1 with no fan and 12.6 with fan. at cruise.

So i guess im buying a 200amp alternator.. thanks for all your help guys :D
 

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The "Big 3" is for any vehicle. It just makes sure there is proper grounding in the vehicle. If you upgraded your alternator positive wire, then you should definately have matching/larger grounds in your Big 3 Upgrade. It is definately worth it to do.

Stephen
 

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Discussion Starter #10 (Edited)
oh ok will check that !! thanks

hmm now that i look at it I upgraded my power wire for my alt but theres no ground going from the alternator to the negative of the battery ? just the harness and the power wire on the alternator

should I just put a ground wire from the alt mounting bolt to the chasis of the car ?
 

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My voltage drops down to 11.5v with hot idle, fan on high, ac blowing, and cheap blue headlights that suck all running at the same time. When the car is cool, the 200 amp alt has no problems keeping it up to almost 14v sometimes above. I also have 4 gauge alt wire and 4 gauge positive to the trunk for my battery (voltage still sucked before battery move). I think I just need to ditch the cheap lights and get some real HIDs.

Theres no sense in grounding your alternator since it should already be grounded through your engine block. Your engine should have a ground wire to the frame/body/battery negative.
 

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Your engine should have a ground wire to the frame/body/battery negative.
..yea that is, at the newest, 11 yrs old and probably 50% corroded on the inside...lol....if you're gonna be drawin lots of juice from one of these cars, it doesnt hurt to replace the engine block grounds, and chassis grounds to the battery
 

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Discussion Starter #13
update;

i installed the 200 amp alternator and now the car starts up with around 11.8 volts and the voltage goes up as the car warms up but the belt squeals really loud when cold?? the new alt brought an overdrive pulley and i read i might need a shorter belt could that be why the belt squeals when cold?

when warm the alt reads 13.8 to 14.1 but when the fan kicks on it still drops to low 12's now think s a grounding issue , yesterday it read 13.7 with the fan on for 25 minutes. i got the optima in the trunk with a short negative cable grounded on the trunk structure.

next im checking engine grounds , any inputs?
 

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Did you do the big three? I would still check the wire to the starter. People mentioned it to me numerous times, but I wouldn't listen. . . until I had to replace it and the symptoms I had (similar to yours) went away. I had purchased a 200amp alternator as well from DB electrical (off of ebay), and it didn't solve my problems either. Are your pulleys lined up properly? My cougar's belt tensioner was able to pick up the slack from the overdrive pulley on mine, but maybe the routing or pulley size is different. Did you make sure that the ground you have is on a clean/unpainted surface?

Stephen
 

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Discussion Starter #15
:Ya i keep forgetting to check that cable to the starter, i havent done the big 3 im going to run a ground wire from the alt mounting bolt to the frame, my pulleys didnt line up at first but i removed metal from the crossbrace and now they do line up, looks like the tensioner picked up the slack on my alt too. and yeS i removed the paint from the ground in the trunk.

ill check what you mentioned tomorrow , thanks
 

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Discussion Starter #16
update

I installed a 4ga wire from the alt mounting bolt to the frame I guess this would be an " engine ground " I been looking at the pics from the big three and I think I might have routed my wiring wrong.

Heres how I have it .. the battery is in the trunk . I got the positive cable from the batt running from the trunk into the passenger side power supply stud, the negative cable is grounded in the trunk support.

i got the alternator power cable running from the alt to the power supply stud, and now the ground from the alt to the frame..

am I missing a cable from the negative of the battery to the back frame or to the alt ?

thanks
 
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